1. Field of the Invention
The present invention relates to an optical pickup that uses a plurality of light beams having different wavelengths to record and reproduce a signal to and from an optical disk, and an optical disk apparatus including such an optical pickup.
2. Description of the Related Art
At present, there are commercially available optical disks, such as a CD, a DVD (Digital Versatile Disk), and a BD (Blu-ray Disk), on which recording and/or reproduction is performed by using light beams having wavelengths different from one another, and optical pickups by which such different types of optical disks can be handled.
The optical system of such an optical pickup includes a plurality of light sources of different wavelengths, a light path-combining optical element that directs the light beam emitted from each of the light sources through a single light path to the optical disk, and an optical isolator that directs the light beam to the optical disk and directs the reflected light beam reflected off the optical disk to a light receiving element.
In recent years, a configuration in which a phase shifting mirror as such an optical isolator is combined with a beam splitter has been proposed (see JP-A-2003-98350), the phase shifting mirror having a function similar to a quarter-wave plate by forming a phase shifting film on an upward-folding mirror disposed immediately upstream of an objective lens.